This invention relates to a configuration detecting device for detecting, the deformation of the front or rear end portion of a steel plate which is caused during rolling, for instance in a hot-rolling process.
The deformation of the front end portion of a steel plate in a hot-rolling process applies a non-uniform load on rolling rolls in succeeding stages, as a result of which these rolls may be damaged, or defective steel plates may be produced.
In order to overcome such drawbacks, heretofore, an operator has visually detected the deformation of the steel plate, and operated a cutter with suitable timing, to sever the deformed portion of the steel plate.
To eliminate this manual process, the following configuration detecting device has been proposed in the art, in which the deformation of the front end portion of a steel plate is automatically detected, the necessary but minimum amount of the deformed portion of the steel portion is cut off and the steel plate thus treated is delivered to the rolls of the next stage, so that the effect of the non-uniform load is eliminated and the rolls are protected from damage.
FIG. 1 is a block diagram showing the conventional configuration detecting device. The width of a red-hot steel plate 1 produced by a hot rolling process is measured at a measurement line 3a with an optical system using a lens 2 and a plurality of photo-electric elements 3 arranged in a line. The outputs of the photo-electric elements 3 are amplified by an amplifier 4, and are then converted into digital data by an A/D (analog-to-digital) conversion circuit 5. That is, the output signals of some of the photo-electric elements 3, on which the image of the steel plate 1 is formed, are set to a logical value "1", while output signals from the remaining photo-electric elements 3 on which the image of the steel plate 1 is not formed are set to a logical value "0". The output of the A/D conversion circuit 5 is applied to a width measuring circuit 6 comprising a counter circuit- so that the number of logical value "1" outputs is counted by the width measuring circuit 6, as a result of which a measurement value corresponding to the width of the steel plate 1 can be obtained.
The measurement value thus obtained is compared with a reference width value W applied through an input terminal 7 in a comparison circuit 8. When the steel plate width is within a predetermined value less than the value W, the comparison circuit 8 applies a cutting signal to a cutter controlling device 9, so that the front end portion of the steel plate 1 is cut off.
More specifically, a plate width kW (where W is the width of the central portion of the steel plate 1, and k is smaller than one (k&lt;1)) of the front end portion of the steel plate, as indicated by the chain line, is detected, so that the front end portion is cut off, as shown in FIG. 2.
The conventional device is arranged as described above. Therefore, in the case where the image of the steel plate is not uniform in brightness because of wide temperature variations in the plate, or scales or water deposits formed on the steel plate, or if a region other than the image of the steel plate is made bright by heat or light which is scattered by particles in the background or in the air, the above device is liable to make errors in digitizing the image of the steel plate.